`nix shell` does not restore default SIGPIPE handler #912

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opened 2025-07-11 20:01:21 +00:00 by cobaltcause · 5 comments

cobaltcause commented

2025-07-11 20:01:21 +00:00

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Describe the bug

Title authored by @dramforever:matrix.org.

Steps To Reproduce

Run e.g. tr -dc '[:alnum:]' < /dev/urandom | head -c 64 > /dev/null
Observe that it works with no error
Run e.g. nix shell nixpkgs#hello
Run the first command again in the shell from the previous step
See error

Expected behavior

The behavior should be the same both inside and outside of a shell, so probably something about nix shell needs to be changed.

`nix --version` output

nix (Lix, like Nix) 2.94.0-dev
System type: x86_64-linux
Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux
Features: gc, signed-caches
System configuration file: /etc/nix/nix.conf
User configuration files: /root/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/root/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/root/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/root/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf
Store directory: /nix/store
State directory: /nix/var/nix
Data directory: /nix/store/ip9h0a9v65z3z8k7b777v038s7ph2fxg-lix-2.94.0-dev/share

(487b37291f)

## Describe the bug Title authored by @dramforever:matrix.org. ## Steps To Reproduce 1. Run e.g. `tr -dc '[:alnum:]' < /dev/urandom | head -c 64 > /dev/null` 2. Observe that it works with no error 3. Run e.g. `nix shell nixpkgs#hello` 4. Run the first command again in the shell from the previous step 5. See error ## Expected behavior The behavior should be the same both inside and outside of a shell, so probably something about `nix shell` needs to be changed. ## `nix --version` output ``` nix (Lix, like Nix) 2.94.0-dev System type: x86_64-linux Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /root/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/root/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/root/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/root/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/ip9h0a9v65z3z8k7b777v038s7ph2fxg-lix-2.94.0-dev/share ``` (487b37291f9344b1c99802fd202667ef73f4b8e8)

cobaltcause added the

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2025-07-11 20:01:21 +00:00

pennae added the

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2025-07-11 21:16:33 +00:00

jade added the

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2025-07-12 02:56:34 +00:00

jade commented

2025-07-12 02:57:31 +00:00

Owner

Tested on macOS on 378b360, does not repro. Unsure if yours is newer, seems that we have had a Situation with the versions getting into the derivation meaningfully.

Tested on macOS on 378b360, does not repro. Unsure if yours is newer, seems that we have had a Situation with the versions getting into the derivation meaningfully.

pennae commented

2025-07-15 17:37:51 +00:00

Owner

doesn't repro under linux either. lix never installs a non-default sigpipe handler, it only masks sigpipe—and nix shell definitely restores the signal mask it was started with before it exec's the inner shell.

doesn't repro under linux either. lix never installs a non-default sigpipe handler, it only masks sigpipe—and `nix shell` definitely restores the signal mask it was started with before it exec's the inner shell.

pennae removed the

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2025-07-15 17:38:26 +00:00